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LibJS+LibWeb: Implement resizable ArrayBuffer support for DataView

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This is (part of) a normative change in the ECMA-262 spec. See:
a9ae96e
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Timothy Flynn 2023-10-15 09:46:09 -04:00 • committed by Andreas Kling
parent 29ac6e3689
commit c7fec9424c
12 changed files with 377 additions and 94 deletions
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59
Userland/Libraries/LibJS/Runtime/DataViewConstructor.cpp
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@ -63,42 +63,71 @@ ThrowCompletionOr<NonnullGCPtr<Object>> DataViewConstructor::construct(FunctionO
if (array_buffer.is_detached())
return vm.throw_completion<TypeError>(ErrorType::DetachedArrayBuffer);
// 5. Let bufferByteLength be buffer.[[ArrayBufferByteLength]].
auto buffer_byte_length = array_buffer.byte_length();
// 5. Let bufferByteLength be ArrayBufferByteLength(buffer, seq-cst).
auto buffer_byte_length = array_buffer_byte_length(array_buffer, ArrayBuffer::Order::SeqCst);
// 6. If offset > bufferByteLength, throw a RangeError exception.
if (offset > buffer_byte_length)
return vm.throw_completion<RangeError>(ErrorType::DataViewOutOfRangeByteOffset, offset, buffer_byte_length);
size_t view_byte_length;
// 7. Let bufferIsFixedLength be IsFixedLengthArrayBuffer(buffer).
auto buffer_is_fixed_length = array_buffer.is_fixed_length();
// 7. If byteLength is undefined, then
ByteLength view_byte_length { 0 };
// 8. If byteLength is undefined, then
if (byte_length.is_undefined()) {
// a. Let viewByteLength be bufferByteLength - offset.
view_byte_length = buffer_byte_length - offset;
// a. If bufferIsFixedLength is true, then
if (buffer_is_fixed_length) {
// i. Let viewByteLength be bufferByteLength - offset.
view_byte_length = buffer_byte_length - offset;
}
// b. Else,
else {
// i. Let viewByteLength be auto.
view_byte_length = ByteLength::auto_();
}
}
// 8. Else,
// 9. Else,
else {
// a. Let viewByteLength be ? ToIndex(byteLength).
view_byte_length = TRY(byte_length.to_index(vm));
// b. If offset + viewByteLength > bufferByteLength, throw a RangeError exception.
auto const checked_add = AK::make_checked(view_byte_length) + AK::make_checked(offset);
auto checked_add = AK::make_checked(offset) + AK::make_checked(static_cast<size_t>(view_byte_length.length()));
if (checked_add.has_overflow() || checked_add.value() > buffer_byte_length)
return vm.throw_completion<RangeError>(ErrorType::InvalidLength, vm.names.DataView);
}
// 9. Let O be ? OrdinaryCreateFromConstructor(NewTarget, "%DataView.prototype%", « [[DataView]], [[ViewedArrayBuffer]], [[ByteLength]], [[ByteOffset]] »).
// 11. Set O.[[ViewedArrayBuffer]] to buffer.
// 12. Set O.[[ByteLength]] to viewByteLength.
// 13. Set O.[[ByteOffset]] to offset.
auto data_view = TRY(ordinary_create_from_constructor<DataView>(vm, new_target, &Intrinsics::data_view_prototype, &array_buffer, view_byte_length, offset));
// 10. Let O be ? OrdinaryCreateFromConstructor(NewTarget, "%DataView.prototype%", « [[DataView]], [[ViewedArrayBuffer]], [[ByteLength]], [[ByteOffset]] »).
auto data_view = TRY(ordinary_create_from_constructor<DataView>(vm, new_target, &Intrinsics::data_view_prototype, &array_buffer, move(view_byte_length), offset));
// 10. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
// 11. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
if (array_buffer.is_detached())
return vm.throw_completion<TypeError>(ErrorType::DetachedArrayBuffer);
// 14. Return O.
// 12. Set bufferByteLength to ArrayBufferByteLength(buffer, seq-cst).
buffer_byte_length = array_buffer_byte_length(array_buffer, ArrayBuffer::Order::SeqCst);
// 13. If offset > bufferByteLength, throw a RangeError exception.
if (offset > buffer_byte_length)
return vm.throw_completion<RangeError>(ErrorType::DataViewOutOfRangeByteOffset, offset, buffer_byte_length);
// 14. If byteLength is not undefined, then
if (!byte_length.is_undefined()) {
// a. If offset + viewByteLength > bufferByteLength, throw a RangeError exception.
auto checked_add = AK::make_checked(offset) + AK::make_checked(static_cast<size_t>(view_byte_length.length()));
if (checked_add.has_overflow() || checked_add.value() > buffer_byte_length)
return vm.throw_completion<RangeError>(ErrorType::InvalidLength, vm.names.DataView);
}
// 15. Set O.[[ViewedArrayBuffer]] to buffer.
// 16. Set O.[[ByteLength]] to viewByteLength.
// 17. Set O.[[ByteOffset]] to offset.
// 18. Return O.
return data_view;
}